Breech closure for guns



THEODORE H. EICKIOFF, OF CLEVELAND, 02H10, ASSIGNOR TO AUTG-ORDNANCE CORPORATION, F NEVI YORK, N. Y., CORPORATON OE NEW' YORK.

BBEECH CLOSURE EUR GUNS.y

[0 @ZZ 'wim/1a t may concern Be it known that l, rnnonoiui H. Elonfrorr, citizen of the United States of America, and resident of Cleveland, in 'the county oit Cuyahoga and State of Ohio, have invented new and .useful improvements in Breech Closures for Guns, of which the following is a specication. y

This invention relates to breech closures for firearms, or' the general class in which there are two members, mutually abutting,` against each other when in breech closing position, with their opposed and contacting `suriaces disposedA at an'angle to the line 'et breech pressure'produced by the detonation or' the explosive in the firearm, and which, as the breech closure opens, slide relatively7 to each other upon saidinclined surfaces. In particular, the present invention is addressed to and adapted to be used in breech closures which operate substantially in accordance with the principle disclosed and ex* enipliied in John Blishs United States Letters Patent, No. 1,131,319, dated March 9, 1915, in' which the inclined surfaced and abutting members are so proportioned in respect to the angle which their inclined suriacesl present to the applied breech pressure that the members lock together at initial and high breech pressure, and upon the subsidence ot th at pressure to a critical lower value, slide with relation to each other to open the breech of the iirearm. The invention in its broader aspects however would also be applicable to breech closures o'l" other types in which high breech pressures are transmitted through abutting surfaces of limited area.

As pointed out in the'patent to Blish, the action'of the cooperating parts of the breech closure locking members under the high pressures of discharge is not in accordance with the ordinarily accepted laws of triction. One theory oi explanation olf the abnormal action of the parts when subjected to such high pressures is based on the wellknown factthat all solid substances have tenaciously clinging to their surfaces layer of condensed gas. Such condensed gras constitutes a very thin lin which may perhaps be oi the order of thickness of' the orbit of a single molecule ot such gas, and it is a matter of common knowledge that it is exceed- Specfieation of Letters Patent.

rar-esteri ree. ia, ieee.

l Application led October '7, 1920. Serialv No. 415,401.

Vingly difficult to remove such film of gas from the surface of a metal, there being apparently an actual cohesion between the metal and the Under ordinary conditions oi pressure and in circumstances under which the usual laws oiC friction apply. it appears reasonable to suppose that the lnis ot' condensed interposed between the surfaces or" adjacent metallic. elements serve in a sense as a sort of lubricant in preventingJ actual physical molecular contact of the inefti lic surfaces. lWhen however, such sur- 'taces are subjected to pressure above a certain critical value, it may be possible that the molecules oi gas lying,` between such surfaces are occluded within the substance of the metallic elements, in which case the molecules of the metallic elements may be considered to come into actual physical conact and to be subjected to the laws oi' molecular at raction. Under these circumstances it would appear to be a reasonable supposition that the cohesive force tending' to hold -the elements in contact, together with the absence oi the liibiicating-gas film, is more than sulicient to overcome any component oli 'the applied force tendingto cause sliding' ot `one o't such elements over the other. Upon release however. olf' `the applied pressure, lwhen the critical point is again reached, the occludcd molecules oi? ras may be regarded as ejected 'from the metallic mass ol the elcnients, thus serving' to break molecular contart the latter and again act as a lubricant therebetween, whereupon the ordinary laws oi Lfriction supervcne.

Whether or not the structure ot' the Blish patent operates in accordance with the above theory or whether or not the breech closure of the present invention operates accordingr to the 'ldisc-every disclosed as aforesaid in said patent to Blish, provided it comprises inclined surfaced members which are pressed together when breech pressure is developed, the said members have to sustain a very con- Sider-able pressure load vat and over their suriaces which are vin actual contact. This a 'function of the total contacting area., andV the object, or one of the objects of this invention is to secure a maximum area of actual contact YbetweenY tivo such operating members of a breech closuremechanism.

By accomplishing this object, the sustained load will be distributed over the' largest available extent ofropposed faces, concentration of load at points or portions Vof such faces with crushing and disintegration of the same will be avoided, the interacting members willendure a maximum of service, and in the particular case of firearm operating according to the discovery patented by John Blish, the initial locking ot the breech closing members will be made more certain and secure, while the release and relative movement of those members Will be effected with certainty at the. critical diminished pressure. i y

No matter hcw carefully and accurately the contacting surfaces of the inclined-abutment breech closure members may be machined and ground, they are never strictly or niicroscopically smooth. As the edges of thelicenest razor discloses marked serrations under the microscope, so also the faces of smoothly-ground metal pieces are characterized by irregularities of contour, albeit of microscopic dimensions,V

lliihen, as has invariably been the case, the inclined-abutment members of a breech closure are made of steel, treated so as to assume hardness in high degree, the material at their opposed surfaces or .faces stubbornly resists all effort tending to distort or modify them.

even momentarily. Such surfaces are cha"- acterized by microscopic irregularities, and though it may seem that the surfaces come into uniformly close contact over their entire opposed areas, in fact they bear against ich other only at the peaks and heights of their faces and it is on these salient portions that the imposed load is concentrated. Microscopic examination of the edge of a `piece of steel, surfaced and treated would be the case with a steel inclined-abutment member of a breech closurev` has made it ,apparent that the steel-tc-steel contact of tivo such members, under breech-pressure load, can not extend over more than fifty per cent of the total area of the opposed faces, even when account is taken of the slight compressibility of steel.

lt is of course practically impossible that the i Aces of two such opposed steel members should even by chance vtit each other microscopically and thus bring into action the entire area of the faces, to resist and distribute imposed pressure-load. The intensity of pressure, when borne by salient points of contact, may be imagined, though it can not be accurately calculated, andthe destructiveV effect of such locallyv concentrated pressure gested that the ,mutually abrasive action of the coacting members themselves may correct the above described condition, let it be borne in mind thatY the metal presenting the face toV be abrade-l is'composed of interlaced crystals, and that` the destruction offa salient crystal merely transfers the salience to its neighbors, and that, after the two members in Contact have smoothed each other as evenly as their mutual abrasion can effect, the farces remain characterized by microscopic nndnlations of contour and will so persist Moreover the crushing and disintegration of such salient portions of the surce under the extreme overload imposed Athereon serves to provide det-ached microscopie particles of hard material Which serve as active abrasive media causing'V a rapid scoring of the surfaces as they slide` one on the other.

is a result of the phenomena above referred to the locking Vabutments of high pressure guns, and indeed of relatively low pressure guns such as those firing .45 calibre pistol cartridgcs,y frequently break during the Yfirst few rounds fired dur-inv the break-v ing'in process; but according to this invention the breaking in process is rendered unnecessary Vand'there is apparently no greater liabilityv to breakage during the first rounds than later. Y

l? or accomplishing the above .mentioned object, a breech closure is provided having two abutment members, the face of one of \:-.hich, ou imposition of breech pressureload, may become the contour-negative, or matrix, .zhe other, so the load is distributed over actically the entirearea of the opposing The means for so securingload-distrilnition lies in the selection of material for face of one of said members which is more yielding than'that of the other and at the same time resilient. Specifically, the best results4 which have been obtained have been with tivo such members, one of which is composed of hardened steel, the other of an alloy having the approximate composition of copper 89%, aluminum 10%, iron 1%. `When the faces of tivo members, one of steel, the other of alloy, both machined and ground as smooth as possible, are pressed together and sustain a load comparable'to Vthat produced on breech closure members under breech pressure, the steel f. ce by reason of the relatively great rigidity of its material reta-ins its microscopically undulated contour substantially unaltered, whereasthe alloy face takes the impress of the steel face.V rlher softer face, While the pressure load is sustained, is a matrix of the other. Doubtless there are higher local concentrations of pressure atthe salientV portions of the steel face than in the hollows between. but the general effect of the assumploads, is readily comprehended. lf it be sugtion by the alloy'facc of a contour which is the negative of that of the steel face, is to distribute the pressure and relieve the concentrations which have characterized Vthe steel-to-steel opposition f similar vmembers as heretofore made. `l/Vhenthus arranged there is no tendency to crush ,and disintegrate the salient points of either of the contacting elements as those of the steel simply sink` into the substance of the opposing membei'7 while such points of the' latter as contact with the steel face are merely depressed due to the superior malleability and softness of the material employed. Thus the formation of detached abrasive particles is eliminated and the destructive scoring and ivear commonly due to the presence of such particles is avoided.

A material of the general type of that above indicated, having av modulus of .elasticity much lower than that of the hardened steel with which it contacts-tendsto yield readily to the passage of such irregularities as the. surface of the steel may present when the parts are moved relatively as in sliding one on the other, but upon passage of such irregularities such material tends quickly to assume itsV original form. Thus While the opposed surfaces may not be mathematically plane, the high resilience of one as respects the other, as Wellas the eXtreme resistance which a material of theclass described presents to the action of oft-repeated stresses, enables the abutting elements to undergo long periods of service Without appreciable Wear.

l ln breech closures which operate according to the Blish specifications above mentionech the momentaryA mutual matrix rev lationship of the locking members, when composed of materials of different rigidities confirms the locking action at high breech pressures.

nthe usual practice of forming gun locks of the class to which'this invention appertains, it is common to harden both the steel lock andthe parts cooperating thereivith and then to assemble the parts in proper operative relationship. Then heat treated steel is thus employed for all of the parts, it is'very difiicult to secure'an accurate tit, the heated treatment subsequent to machining introduces slight in- .accinacies which can only be overcome by a slow and laborious process of lapping with tine abrasive and breaking in by the -repeated operation of the assembled parts.

A further object of the present invention is to facilitate the ittingand assembling of the breech lock and its associated parts. The employment of a relatively soft but strong alloy such as above referred to or a substance having similar physical properties as a material for one of the cooperating elements, provides one mode of accomplishingthis latter object, it being found, particularly When the locking memberl is formed of such material, that it readily accommodates itself to the inaccuracies Yinadjacent parts, thus avoiding much expenditure of time and labor and rendering the locks more truly interchangeable.

With the foregoing explanation of the principle on which the invention operates7 the illustrative example shown in the drawings hereto annexed will be readily understood. y

In these drawings, A

Fig. l is a longitudinal cross-section of so much of a gun embodying the present invention as is necessary to disclose its mode of application thereto, the parts being shown in firing position;

Fig. 2 is a view similar to Fig. l showing the parts in the position Which they occupy immediately after firing and unlocking of the breech lock;

Fig. 3 is a transverse or cross sec the line 3 3 of Fig. 2; y

F ig. i is a fragmentary longitudinal section on the line lf-4 of Fig.

ion on Figure 5 is a transverse 'section on the line of Fig. l;

Fig. 6 is a perspective view of the locking element employed in accordance With this invention; and

Fig. 7 is a diagrammatic view illustrating the annular relation of certain of the parts employed.

The device forming the subject matter of this application constitutes an improvement in the mechanism disclosed in the application of Oscar rV. Payne, Ser. No. 282,6-12, filed March 14, 1919. ,to which application reference may be had for a more complete disclosure of the particular gun chosen for the purpose of illustrating the present invention.

l is a receiver upon which the various operative parts are'snpported and Whichis hereinafter referred to as the frame or frame member. 2 is the gun barrel having aV firing chamber 3, the gun being provided With a magazine 4l. is the breech-block slidably mounted. in the frame to move toward and from the tiring chamber. (3 is a breech lock for retaining the breech-block in firing position, and 7 is a ring member longitudinally slidable upon the breechblock and toward and from the ring chamber. 8 is an actuating spring serving normally to move the breech-block into closed position and alsov as the operating means for the tiring member. The firing member '7 comprises a forwardly extending lportion 9 preferably guided in a suitable slot in the forward part of the breech-block and is furnished with a finger piece 1() by means ofivhich the tiring' member may be Amanuallyr'etracted. rlhe firing member is also provided with a rear portion ll slidably guided in a longitudinal cavity or channel in the upper rear portion of the breechbloclr. lWithin this cavity is also mounted the spring 8.

The rear portion ll of the firing member is provi-led with a downwardly and rearwardly inclined slot. l2 having a forward wall 13 and a rear wall la. positionthe lower edges of the walls l-rll intersect the walls 13a-lla respectively of pair of forwardly and downwardly inclined slots in the side walls of the frame or receiver, of which one is indicated at 1Q Fig. f-l, formed in the frame member l at opposite sides of the breech-block 5.

The locking member 6, shown in perspective in Fig. 6, comprises a horizontal bar 1G serving to connect apair of spaced' members l'-lS lying` in parallel vertical planes.V

The forward and rearV edges of the members l7-l8 form inclined surfaces lil-19%- --20a respectively, and the front and rear surfaces of the member 16 are also inclined, but downwardly and rearwardly, the inclination of the latter surfaces corresponding to that of the surfaces 13-14 of the firing member with which they are arranged to engage. UponV the outer surfaces of the members l'T-lS respectively are provided outstanding lugs 21-22 which have forwardly and downwardly inclined surfaces 2id-23- ZtT-Qill respectively. rThe inclination of the surfaces QB--Qa and 2A-24a is substantially that of the walls 13a 14a of the slots 12a in the frame, such surfaces being adapted to slidably engage said walls. v f

The breech-block 5 at opposite sides of the cavity within which the-spring S is seated is provided with upstanding walls having forwardly and downwardly inclined slots 25 therein, such slots having forwardly Vand downwardlyY inclined front and rear walls 2G- 27. VThe inclination of the walls 26-27 corresponds to that ofthe surfaces 19--1-9, OJQO on the locking member with which such surfaces have sliding engagement.

Referring to Fig. 7, the angle fb, which is the difference between the angle f of the lock-frame surfaces and the angle o of the lock-block surfaces, is the eective angle for restraining the breech-block in closed position upon firing. If the breech closure is to operate on the Blish principle, this angle should be almost equal to the angle of repose for the particular materials and pressures employed. The firing pin angle is designated as a negative angle inasmuch as it slopes in a direction opposite to the other angles. The angle fm of the firing pin may be varied considerably, but should not be made so large as to cause undue friction between the firing member and the locking bolt nor should it be made too small inasmuchV as in the latter case the firing member would not be projected forwardly relatively to the lVhen in ring breech-block with suilicient momentum to lire the cartridge.

The frame l with its guiding surfaces 13a-lla is formed of steel and VVafter machining is .preferably subjected to a cyaniding process to secure the necessary hardness in the wearing surfaces. The breech-block with its surfaces 26-27 may also be formed of the same material and heat-treated in a similar' manner. The lock 6 however, is formed of a material relatively softer and more malleable than such heat-treated steel, and of a. character such that when subjected to exceedingly high pressures such as those generated in the firing chamber of the gun, theV lock (-3 will accommodate itself to the microscopic irregularitiesV in the guiding surfaces of the relatively harder frame and breech-block, receiving anvimpress thereof in its surface and thus in effect becoming a contour-negative or matrix Vof such harder elements. Thilo it is contemplated that many materials may be found which would fulfill the necessary requirements, experiment has shown that a copper alloy having the approximate composition of copper 89%, aluminum '10% and iron 1% is especially well adapted to this use,V The ratio of hardness of such an alloy to the heat treated steel may be approximately as one to four while at theV same time providing the necessary compressive strength to enable the lock to perform: its functions in a satisfactory and serviceable manner.

The modulus of elasticity of such an alloy being small as compared to that of steel, the locking member readily yields to the projections on the surfaces of the parts cooperating therewith, but by' reason of its great resiliency and ability to withstand repeated stresses without deterioration, the bolt receives no appreciable parmanent injury from the dragging of such projections thereover. Thus by the employment of a lock of relatively soft material such as above indicated the effects of abrasion between the lock and its cooperating parts is almost entirely eliminated, This effect is probably dueV in part also tothe fact that there is no crushing and breaking down of the meeting surfaces such'as apparently occurs when a steel-on-steel contact is employed, and thus no production of minute Vdetached particles of hard metal which would if present rapidly' score and abrade the contacting faces of the parts.

While as hereinabove specifically described, the locking member has been designated as being of. the softer material, it is to be understood that many, if not all of the advantages occuring from the employment of such a materialv may be secured by making the locking member of heat-treated steel or other hard material and utilizing the softer material in the productions of all,

or of such parts only if preferred, of the breech-block and receiver as cooperatively engage the locking member.

In applying the invention to guns in which an abutment on the breech-closure abuts directly against an abutment on the receiver, instead of through the medium of a locking member such as 6, either the breech closure abutment or the receiver abutment is made of the softer material.

I claim:

1. In a gun, abutment mechanism for opposing the explosion reactions 'comprising a pair of pressure receiving elements relatively movable under breech pressure and having mutually engaging surfaces, the surfaces of the respective elements being of such a relative degree of hardness as to permit irregularities of one to be impressed in the other. l

2. YIn a gun, abutment mechanism for Opf posing the explosion reactions comprising a Ypair of pressure receiving elements relaa tively movable under breech pressure, ysaid elements having such different degrees of -hardness as to permit adjacent surfaces thereof to be brought substantially into uniform molecular Contact under the imposition of such high pressure.

Y 3. In a gun, abutment mechanism for opposing the explosion reactionscomprising a plurality of pressure receiving elements relatively 'movable Lunder breech pressure, said elements having opposed surfaces and being constructed of. materials having different degrees of hardness to permit physical contact of said surfaces throughout substantially the entire area thereof .upon imposition of such pressure.

4. In a gun, abutment mechanism for opposing the explosion reactions comprising a pair o1' relatively movable pressure receiving elements having engaging surfaces, one of said elements being movable in a path inclined to the direction of applied pressure, the engaging surface of one of said elements being of a material having a substantially lower modulus of elasticity than the material of the cooperating surface of the other element.

5. In a gun, mechanism for opposing pressures of the order of 50,000 pounds per square inch, a pair of elements relatively7 movable under breech pressure having opposed pressure transmitting faces, the face of one of said Velements being of a degree of hardness substantially different from that of the other face.

6. In a lock mechanism for guns, a movable locking element and an abutment element therefor, one of said elements being of a hardened ferrous material and the other thereof comprising a material having a Brinell hardness number of approximately one fourth that of such ferrous material.

7. In combination in a gun, a movable locking element and an abutment element therefor,l said elements being relatively mov* able under breech pressure, one of said elements being oflieat treated steel and the other thereof being of a copper alloy.

8. Ina locking machanism for guns, in combination a pair of engaging abutment elementsl relatively movable under breech pressure, one of said elements being of a hardened ferrous alloy, and the other theres of being of a material relatively malleable as respects such alloy.

9. In a gun, abutment mechanism for opposing the explosion reactions comprising a breech block and a lock member movable relatively to each otherunder breech pressure. said breech block having a hardened steel. surface abutting against said member transversely of the line of breech pressure and said member being of a copper alloy.

10. In a gun in combination a breech block, a lock member movable relatively thereto, said breech block having a hardened steel surface for supporting said member against the breech pressure and said member being of'a copper aluminum alloy.

11. In a gun, a fixed abutment and breech closing mechanism having a part movable into and out of position in front of said abutment, said part being'formed of a copper alloy and being movable out of position by breech pressure.

12. In aguil of the class described, a relativelylfixed member having an abutment element therein, a breech block slidable with respect to said fixed member, and alocli member engageable with said abutment element and contacting with said breech block, said lock member being of a material relatively soft as compared with the material of the breech block and the abutment.

13. In a gun, a frame member having an inclined guide slot, a breech block slidable relatively to said frame member and provided With an inclined guide slot, and a loclc ing bolt of a copper alloy mounted for sliding movement Within the said slots.

111-. In a breech lock mechanism for guns, in combination, a locking member movable under breech pressure, and an abutment member supporting said locking member against breech pressure, one of said members being ofV hardened steel and the other of said members being of a softer material capable of receiving an impress of the microscopic irregularities of the co-operating surface of the other under the action of ballistic pressures,

15. In av breech locking mechanism of the Blish type, relatively movable members for lopposing the ballistic pressures of discharge, one of said members being' of a relatively softer material than the` other Whereby greater endurance under repeated stress and better Contact of the members is achieved. Y

i6. .ln a breech locking mechanism of the Blish type, a pair` of pressure receiving elements havingengaging surfaces inclined to the direction of breech pressure, said elements havingl such diiierent degrees ot hardness respectively that pressure applied to one ot said elements is transmitted to the other tnereo and distributed in a substantially uniform manner over the entire area of 'he contacting*I surfaces of said elements.

l?. :"i, rearm comprising` a iframe,r a breech block. a locking member having surfaces constructed and arranged for engagement with abutment elements of the frame and breech block respectively, said elements being inclined to the direct-ion oin` breech pressure and of relatively greater hardness than the surfaces of saidV locking member with which they engage. Y Y

1S. l'n a breech lockingmechanism or' the Blish type, a frame, a breech block slidable thereon, said block having an abutment element inclined to its path of movement, and a locking' member engaging saidv abutment element and an inclined abutment element of the frame, said locking` member being of a material such as a copper-aluminum alloy whereby under the action or"Y high ballistic pressure it is forced into actual physical contact with substantially the entire area of the cooperating surfaces ot said abut-ments.

19. In a breech locking' mechanism, in combination a frame, a breech block slidable relatively thereto, said frame and said block having` abutment surfaces inclined to the direction Voit breech pressure and or" the order of hardness oi heat treated steel, and

vformed ot an alloyV containing a copper-alloy locking member engageable `with said abutment surfaces and constructed and Varranged to. lock said block in closing` position under ballistic pressure and to release said block upon Vdiminution ot pressure t a predetermined degree.

20. In a breech locking mechanism of that type having' a movable breech closure and means for holding said closure in opposition to breech pressure, in combination lock, and an abutment member having an inclined face for engagement by said lock, said lock and said member being of material of such relative physical characteristics as to cause one of them to become the contour-negative or matrix of the other when subjected to ballistic pressure. Y

:ZLIn ja breech locking mechanism, in combination a locking bolt, and a part c0- operating therewith, said bolt andv part being4 relatively movable under breech pressure and being constructed of materials-having such relative hardness as to permit rugosities of one to be embedded in theV su 1tace of the other when such parts are subjected to ballistic pressure.

22. In a gun, mechanism for opposing the explosion reactions comprising opposing` abutments, one of the abutments being;

approximately nine-tenths copper.. Y Y

23. In a gun, mechanism for opposing' the explosion reactions comprising opposing abutments, one et' the abutments being formed ,of an alloy containing approximately nine-tenths copper and approximately one-tenth aluminum.

VSigned by me at Cleveland, Ohio, this first day of October, 1920.

THEODORE H.` EICKHOF'F. 

